The invention relates to golf clubs and, in particular, to putters.
Putters are generally manufactured with upright faces so that the club will strike the ball squarely propelling the ball on the ground a short distance. In this regard, the putter is different from other clubs which seek to achieve varying degrees of loft if at all, causing the ball to fly varying amounts of distance. To the contrary, a putter should be designed so that the ball cam be accurately propelled shot distances of a few feet, or longer distances of several yards and so the ball will only slightly fly, or not at all.
In the prior art, there are many mass relieved putters, most having mass relieved in the upper portion of the putter, leaving a putter which is bottom heavy. An example is U.S. Pat. No. 5,857,922 to R. Delio. The ""922 patent shows a square club face, with mass relief, intended to produce negative loft. Mass relief is in the center of the club, directly behind the face leaving the heel and toe portion of the club undisturbed. The center of gravity of the club head is intended to be above the center line of the ball, imparting overspin on the ball which keeps the ball in contact with the ground.
U.S. Pat. No. 5,494,288 to R. Jimenez et al., a golf putter is disclosed having similar mass relief and once again, heel and toe regions are maintained with the standard amount of mass. The club shaft is brought into contact with the sole of the club. This design is said to eliminate Dutter face twist when the ball is struck.
A large number of other patents have various mass relief features, for various purposes, but all producing a club which has a substantial sole or bottom surface. A problem with a heavy sole of the putter is that the center of gravity of the club lies below the center of the ball when the ball is struck. This tends to produce backspin, sometimes with loft, with an unpredictable result. An object of the invention was to devise a putter which has limited and controlled loft, resists twisting and generally presents a higher center of gravity for solid force transmission toward the center of a golf ball.
The above object has been achieved with a new putter design, with mass relief which increases the height of the center of gravity of the club. Over reasonably short distances, the best place to transmit force to a golf ball is at a point in alignment with the center of the ball. The club of the present invention reduces the size of the sole of the club to only a few millimeters while the top surface of the club remains the same. The mass relieved region of the club is immediately behind the face and below the top surface between the heel and toe regions. The club is fabricated from a block of metal, with mass relief achieved by milling regions behind the face of the club and below the top surface. Because most of the club head mass is removed at the bottom of the head, the club design has inverted mass relief compared to clubs of the prior art where mass relief was mainly at the top of the head. Some mass is left at the heel and toe regions so that these formed balaced regions, keeping the club from twisting. A pair of ribs is left immediately behind the face for strength and definition of a sweet spot between the ribs. A hosel arm makes contact with the top surface of the club above the sweet spot so that the club can squarely address a golf ball with ease of alignment. The sweet spot of the club may be stiffened with the addition of a plug of a heavy metal, such as depleted uranium. This quickens the ball release upon impact, yet the weight of the club is comparable to ordinary clubs.